Scherrer S S, de Rijk W G
Department of Restorative Dentistry, University of Texas Health Science Center Dental School, San Antonio 78284.
Int J Prosthodont. 1992 Nov-Dec;5(6):550-7.
This in vitro study measured the changes in the fracture resistance of posterior crowns as a function of crown length. The crowns, 10 for each group, were made of a feldspathic porcelain (Ceramco), a glass-ceramic material (Dicor), and an alumina-reinforced glass (In-Ceram). Three different crown lengths were tested on acrylic resin dies. The restorations were fractured in a testing machine using a steel ball, 12.7 mm in diameter, that contacted the occlusal surface at three distinct points. Statistical analysis was performed using the Weibull distribution. The fracture resistance increased significantly with increasing crown length for all crown materials.
这项体外研究测量了后牙冠抗折性随冠长度的变化。每组10个冠，分别由长石质瓷（Ceramco）、微晶玻璃材料（Dicor）和氧化铝增强玻璃（In-Ceram）制成。在丙烯酸树脂模型上测试了三种不同的冠长度。使用直径为12.7毫米的钢球在测试机中使修复体折断，钢球在三个不同点接触咬合面。使用威布尔分布进行统计分析。所有冠材料的抗折性均随冠长度的增加而显著增加。
